<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>basic_waitable_timer::cancel_one (2 of 2 overloads)</title>
<link rel="stylesheet" href="../../../../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<link rel="home" href="../../../../index.html" title="Asio">
<link rel="up" href="../cancel_one.html" title="basic_waitable_timer::cancel_one">
<link rel="prev" href="overload1.html" title="basic_waitable_timer::cancel_one (1 of 2 overloads)">
<link rel="next" href="../clock_type.html" title="basic_waitable_timer::clock_type">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../../../asio.png"></td></tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="overload1.html"><img src="../../../../prev.png" alt="Prev"></a><a accesskey="u" href="../cancel_one.html"><img src="../../../../up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../home.png" alt="Home"></a><a accesskey="n" href="../clock_type.html"><img src="../../../../next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="asio.reference.basic_waitable_timer.cancel_one.overload2"></a><a class="link" href="overload2.html" title="basic_waitable_timer::cancel_one (2 of 2 overloads)">basic_waitable_timer::cancel_one
          (2 of 2 overloads)</a>
</h5></div></div></div>
<p>
            (Deprecated: Use non-error_code overload.) Cancels one asynchronous operation
            that is waiting on the timer.
          </p>
<pre class="programlisting">std::size_t cancel_one(
    asio::error_code &amp; ec);
</pre>
<p>
            This function forces the completion of one pending asynchronous wait
            operation against the timer. Handlers are cancelled in FIFO order. The
            handler for the cancelled operation will be invoked with the <code class="computeroutput">asio::error::operation_aborted</code>
            error code.
          </p>
<p>
            Cancelling the timer does not change the expiry time.
          </p>
<h6>
<a name="asio.reference.basic_waitable_timer.cancel_one.overload2.h0"></a>
            <span><a name="asio.reference.basic_waitable_timer.cancel_one.overload2.parameters"></a></span><a class="link" href="overload2.html#asio.reference.basic_waitable_timer.cancel_one.overload2.parameters">Parameters</a>
          </h6>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">ec</span></dt>
<dd><p>
                  Set to indicate what error occurred, if any.
                </p></dd>
</dl>
</div>
<h6>
<a name="asio.reference.basic_waitable_timer.cancel_one.overload2.h1"></a>
            <span><a name="asio.reference.basic_waitable_timer.cancel_one.overload2.return_value"></a></span><a class="link" href="overload2.html#asio.reference.basic_waitable_timer.cancel_one.overload2.return_value">Return
            Value</a>
          </h6>
<p>
            The number of asynchronous operations that were cancelled. That is, either
            0 or 1.
          </p>
<h6>
<a name="asio.reference.basic_waitable_timer.cancel_one.overload2.h2"></a>
            <span><a name="asio.reference.basic_waitable_timer.cancel_one.overload2.remarks"></a></span><a class="link" href="overload2.html#asio.reference.basic_waitable_timer.cancel_one.overload2.remarks">Remarks</a>
          </h6>
<p>
            If the timer has already expired when <code class="computeroutput">cancel_one()</code> is called,
            then the handlers for asynchronous wait operations will:
          </p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
                have already been invoked; or
              </li>
<li class="listitem">
                have been queued for invocation in the near future.
              </li>
</ul></div>
<p>
            These handlers can no longer be cancelled, and therefore are passed an
            error code that indicates the successful completion of the wait operation.
          </p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2018 Christopher M. Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
</div></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="overload1.html"><img src="../../../../prev.png" alt="Prev"></a><a accesskey="u" href="../cancel_one.html"><img src="../../../../up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../home.png" alt="Home"></a><a accesskey="n" href="../clock_type.html"><img src="../../../../next.png" alt="Next"></a>
</div>
</body>
</html>
